Talking Trees

Dirk Dujesiefken

Arboricultural Academy Season 2025 Episode 160

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0:00 | 16:18

In this Friday episode of Talking Trees, we pay tribute to one of the most influential figures in modern arboriculture—Prof. Dr. Dirk Dujesiefken. His career has shaped the way we understand, teach, and care for trees in urban environments across Europe.

We discuss:

  • His early fascination with nature protection and the urban role of trees, which led him from studying wood to researching living trees and tree care systems
  • The founding of the Institute for Tree Care and its three central pillars: education, research, and consulting
  • His pioneering work in advancing the CODIT (Compartmentalization of Decay in Trees) model and tree condition assessment methods
  • His contributions to national and European standards for tree management, helping unify and raise the quality of arboricultural practices
  • How he addresses emerging challenges such as climate change, tree diseases, and urban pressure, and his advice for the next generation of arborists

Dirk Dujesiefken’s work continues to inspire a science-driven, practical, and respectful approach to working with trees.

Background information:

  • ArboChat Plus / Dirk Dujesiefken / Hamburg / 2023


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Introduction to Dirk Duyesefken

Roger

Talking Trees with Lillian Jad. Welcome to Talking Trees. In today's episode we bring you an inspiring conversation with Dirk Duyesefken, a highly respected German arborist. We'll explore his lifelong dedication to tree care, his journey to founding the Institute of Arboriculture in Hamburg and his vision for the future of the field. To watch the full interview, head over to youtubecom at Arbor East. The link is in the description. Let's dive into this enlightening conversation.

Jad

Welcome back everybody for another deep dive.

Lilly

Yeah, this time we're really branching out, aren't we?

Jad

We are it's all about urban forestry this time're really branching out, aren't we? We are it's all about urban forestry this time, and we've got an amazing interview to dig into from the 2023 Arbor Chat and this interview with Duk DeJosefekian. It's packed with insights.

Lilly

He really is a legend in the field.

Jad

Okay, so for those just tuning in who might not be familiar with DeJosefekian's work, set the stage for us.

Lilly

Well, you could say he's been a champion for trees his whole life. I mean, we're talking decades of experience, research and advocacy. What I find most fascinating about him is how his own path kind of mirrors this growing awareness of trees in urban settings.

Jad

Right, it's like his career blossomed right alongside the field itself.

Lilly

Exactly.

Jad

So take us back to his early days. He starts out studying forestry right Back in the 1970s.

Lilly

Yeah, which think about it back then arborist as a term, as a profession, it wasn't really a thing yet.

Jad

It's crazy, isn't it, how much things have changed.

Lilly

It really is. But even back then, during his forestry studies, you can see this fascination with the urban environment starting to take root for Dujasifkin.

Early Career and Turning Points

Jad

And a lot of that stemmed from a pretty unique experience he had right, the 1973 International Garden Exhibition in Hamburg. Oh, absolutely a turning point for him. I can only imagine this young Dujasifkin, probably surrounded by concrete, his whole life up to that point.

Lilly

And suddenly, boom, he's immersed in this world of urban green spaces, seeing firsthand how they could transform a city. You know.

Jad

It must have been eye-opening.

Lilly

Completely. And what's really interesting is this was all happening right when the book the Limits to Growth was making waves.

Jad

Yeah, that was a big one 1972. Right Long before like mainstream environmentalism Right ahead of its time Right, but it really got people thinking about our impact on the planet and I imagine, for Dujas, ifikan, those two things the garden exhibition and limits to growth it all just clicked, didn't it.

Lilly

Yeah, it did. Yeah. He saw the vital role trees play in a city's well-being and, at the same time, this growing need to protect them, especially with cities becoming more and more concrete jungles.

Jad

Right, because it's not just about planting trees. It's about understanding them, advocating for them, making sure they're actually thriving.

Lilly

And that's really the heart of Dujasufan's work. He doesn't just love trees, he fights for them.

Jad

And a big part of that fight was recognizing a need for, like formal structures around tree care, which leads us to the late 1980s right.

Lilly

Exactly DuJasifin. At this point he's deep into his research but he starts to see this glaring gap in the field of arboriculture.

Jad

Like what was missing.

Lilly

Well, for one, there wasn't really a unified approach to research, like arborists were doing great work, but it was kind of scattered, you know, and there wasn't a central place for sharing knowledge, for learning.

Jad

So there was this need to bring it all together Exactly, and that's where Drew Jasekin steps in and founds the Institute for Bound Flage.

Lilly

Huge moment. He saw a need and he took action.

Jad

He really did, and this wasn't just some vanity project. This institute became the foundation for so much of the progress in urban forestry we see today.

Lilly

Totally agree, and it's all rooted in those three pillars. He established education, research and consulting.

Jad

Okay, so unpack those a little for us. How did they work together? What was the vision there?

Lilly

Well, the education part was huge. It was about taking all this complex tree science and making it accessible, not just for scientists but for practitioners, for enthusiasts, for anyone who wanted to learn.

Jad

So almost like democratizing tree knowledge in a way.

Lilly

right, yes, and then, of course, you have the research pillar, which, for Dijasifkin, it wasn't just about doing a few studies here and there, it was about this ongoing dedicated exploration into how trees function, especially under stress in urban environments. I mean his dedication to research over 40 plus years. It's incredible really.

Jad

And it's that research that really forms the backbone of everything else right, the education, the consulting, it all stems from this solid foundation of knowledge.

Lilly

A hundred percent. But then you need that third piece, the consulting, because knowledge is only as good as its application.

Jad

Exactly so how did that play out? The consulting?

Lilly

Well, it's about bridging that gap between the science and the real world, taking all those research findings and working directly with communities, with cities, to actually address tree-related problems.

Jad

So it's like this beautiful cycle the research fuels the education, which then informs the consulting, which then sparks new research questions.

Lilly

A perfect ecosystem for urban tree care.

Jad

I love it, and it's through this multifaceted approach that Dujasufcan makes some of his most significant contributions, wouldn't you say?

Lilly

Absolutely.

Jad

And his research on pruning. It revolutionized the way we think about tree care.

Groundbreaking Research on Trees

Lilly

It really did, you see, before Dujasufcan pruning. It revolutionized the way we think about tree care. It really did, you see, before Dijazifkin pruning. It was often seen as this oh, I don't know, like a purely aesthetic thing.

Jad

Right, just making the trees look nice and tidy.

Lilly

Exactly, but his research showed how crucial proper pruning is for a tree's health. Like if you don't prune correctly, you can actually weaken the tree's natural defenses.

Jad

So it's not just about making them pretty, it's about understanding their immune system essentially.

Lilly

Precisely and how to work with those systems, not against them. Dujazivkin's research showed that with the right techniques, pruning can help trees thrive. They live longer, healthier lives, and the impact of this I mean his work on pruning has been translated into like 10 languages, with more on the way. I think they're working on Chinese and Hebrew versions as we speak.

Jad

Wow, that's incredible Talk about a global movement for better tree care.

Lilly

It really is and this deep understanding of tree biology. It's also at the heart of his work on the Kodite model.

Jad

Okay, kodite, compartmentalization of decay in trees Right Sounds kind of intense.

Lilly

It is, but it's also fascinating. Basically, Duterte-Zivton cracked the code on how trees heal themselves.

Jad

OK, I'm listening.

Lilly

Yeah.

Jad

Tell me more, because I thought trees didn't heal the same way our bodies do.

Lilly

They don't. So when a tree gets wounded, it doesn't just like regenerate new tissue. Instead, it compartmentalizes the injury. It basically walls it off to stop the decay from spreading.

Jad

It's like it builds an internal barrier or something.

Lilly

Yeah, and the CODIT principle as Dujazifkin expanded it. It helps us understand how those barriers form, how effective they are, even how different pruning practices can impact the process. It's like having this like x-ray vision into the inner workings of a tree. Having this like X-ray vision into the inner workings of a tree.

Jad

That's a great way to put it, like we can now read a tree's history, its health, by understanding how it's compartmentalized. These past injuries.

Lilly

Exactly and that knowledge. Then we can use that to make more informed decisions about how to care for them. Moving forward and this is where his work in Hamburg comes in, because in the 80s his team they pioneered the first tree risk assessment system in the city.

Jad

This was at a time when, wasn't it like, if a tree looked even a little bit iffy, they just like chop it down.

Lilly

Pretty much Decisions about removing trees. Yeah, they were often driven by fear back then, right.

Jad

Big tree, scary Old tree, get rid of it.

Lilly

Yeah, and due to Sifkin's system, it really challenged that. It brought in this new era of like informed decision making, using science-based assessments to figure out, ok, which trees actually pose a risk and which ones can be, you know, safely preserved.

Jad

It's like moving away from this, like knee-jerk reaction to a more nuanced data-driven approach.

Lilly

And that was huge, especially for mature trees, which Duzisifkin always emphasizes how important they are. They're like the crown jewels of our urban forests.

Jad

Oh, I bet, because those older trees they just provide so much more, don't they?

Lilly

So much Shade carbon absorption they clean the air. Losing a mature tree, it's like losing a vital organ, almost.

Jad

Right. And speaking of knowledge, do you see, if you can? He's not one to keep all his discoveries locked away in a lab somewhere. He's written like tons of books and articles, hasn't he?

Lilly

He's incredibly prolific. He really wants to make this knowledge accessible to everyone, not just scientists. He's written about tree biology care protection. His writing has been so influential even beyond academia.

Jad

And it's not easy to take complex scientific concepts and make them understandable and, dare I say, interesting for a wider audience.

Lilly

He's really good at it and on top of all that, he's an honorary professor.

Jad

Talk about dedication. He could just be relaxing on a beach somewhere.

Lilly

He's got this passion for nurturing the next generation of arborists Absolutely. And it's not just formal education either. He's also like a driving force behind these massive conferences the Deutsche Bonfleischetage, for example.

Jad

Okay, for those of us who don't speak German, what is that?

Lilly

Oh sorry. It's one of the biggest arboriculture conferences in Germany. It brings together scientists, practitioners, policymakers everyone who's passionate about trees.

Jad

What a cool idea.

Lilly

It is, and Dujeskin has been a lead in voice at those for years advocating for better communication and collaboration in the field.

Jad

So it's like he's building bridges between research and the real world, making sure that all this knowledge is actually being used to make a difference.

Facing Urban Tree Threats

Lilly

And that's what's so inspiring about his work. He's not content with just studying trees, he wants to protect them. But he's also realistic about the work. He's not content with just studying trees, he wants to protect them.

Jad

But he's also realistic about the challenges. Oh, I bet, because even with all the progress we've made, there are still some pretty big threats facing urban trees, aren't there?

Lilly

Absolutely, and Dujasifkin himself identifies three main ones climate change, emerging diseases and, of course, good old fashioned urbanization.

Jad

Okay, yeah, those are pretty big ones. Let's dive into those. Climate change first, I guess, because that feels like the 800 pound gorilla in the room these days, doesn't it?

Lilly

It really does. As temperatures rise and rainfall patterns change, even established trees are showing signs of stress.

Jad

We're seeing it everywhere, aren't we? Drought, heat, stress, trees are struggling.

Lilly

And it's easy to forget how much we rely on those trees, especially in urban environments. They do so much for us, you know cooling our cities, cleaning the air.

Jad

They're not just pretty decorations right, they're essential for our well-being and, like you said, it's not just climate change they're dealing with no.

Lilly

There are all these new diseases and pests popping up too which do you just?

Jad

seeievkin talks about a lot, right, like he mentions those diseases myceria on plain trees and pseudomonas on horse chestnuts. They're becoming more and more common.

Lilly

Yeah, and those are nasty worms. They can wipe out entire populations of trees and because they're often introduced from other parts of the world, our trees they haven't had time to build up any resistance.

Jad

Their immune systems just aren't ready. So it's like they're being hit with this double whammy climate change is stressing them out, and then these new diseases come along and it's like game over, exactly.

Lilly

And then, on top of all of that, you've got urbanization, which is almost like a silent killer.

Jad

How so.

Lilly

Well, think about it this way as more and more people are crammed into cities, our urban forests, they're losing their habitat.

Jad

It's like we're loving them to death almost. We want more trees for all the good they do, but we're also squeezing them into these tiny little spaces.

Lilly

Exactly. And to Jacev Ken he says this is why we need a fundamental shift. We need to move away from this tree care mindset to a tree site protection mindset.

Jad

Tree site protection. Okay, I like the sound of that. What does he mean by that?

Lilly

So tree care that's often focused on the individual right. How's the tree doing? What can we do if it gets sick? But tree site protection, it's much bigger.

Jad

It's about the whole environment the tree lives in right.

Lilly

Yeah, the soil, the roots, making sure the trees have enough space. We have to remember a tree isn't an island, it's part of this interconnected web.

Jad

Which we forget sometimes when we're sticking them in these little concrete squares.

Lilly

All the time, and Josephkin is a big believer in teamwork. It's not just on arborists, it's architects, city planners, all of us working together to make our cities places where trees can actually thrive.

Jad

So it's not just about planting more trees. It's about designing our cities in a way that supports them long term.

Lilly

Yes, and this is where Joseph Milliken gets really fired up about preserving mature trees. He's not a fan of that term climate trees.

Jad

I've heard him talk about that. It's like a pet peeve of his or something.

Lilly

Well, because he's like, all trees are climate trees, they all contribute.

Jad

What worries him is this rush to just plant new trees sometimes overshadows the incredible value of the mature trees we already have, because a brand new tree, even if it's some super species or whatever, it's not going to give us the same benefits as a hundred-year-old oak.

Advocacy and Future Vision

Lilly

No way, those mature trees. They're the heavy lifters. They're absorbing so much carbon, providing shade, cleaning the air. The root systems are holding everything together. Losing one of those, it's a tragedy.

Jad

It's like losing a library or something. All that history, all those benefits just gone.

Lilly

It's tough because you need both right. Planting new trees is important for the future, but we can't forget about the ones who are already here working so hard for us.

Jad

It's about respecting our elders, at least in the tree world right.

Lilly

Exactly, and it goes back to that tree site protection idea creating an environment where trees can thrive for generations.

Jad

So, even though Dujasifkin is this like world-renowned scientist, there's also this real activist spirit to his work, isn't there?

Lilly

Oh, huge. This isn't just academic for him. He wants to get his hands dirty and save trees, Like right now he's doing this really little project with the University of Hamburg they're trying to save horse chestnut trees.

Jad

From that bacteria.

Lilly

Yeah.

Jad

The one that's been wiping them out everywhere.

Lilly

That's the one Pseudomonas. It's nasty, but what I think is so great is they have this goal to have a solution within three years. They're not messing around. This is real world problem solving.

Jad

That's so inspiring, though, because it shows how much power there is in applied knowledge, right? They're taking what they know and actually using it to make a difference.

Lilly

Absolutely, and Dujasifkin is always pushing for that.

Jad

Because it's one thing to say protect trees, it's another thing to actually give people the tools to do that right. Absolutely. It's another thing to actually give people the tools to do that right, especially with all the development happening 100%.

Lilly

He wants to make sure everyone, from developers to everyday citizens, feels empowered to advocate for trees.

Jad

It's like he's this amazing mix of scientist and advocate, and so humble.

Lilly

The best combination and, honestly, that's what makes him such an effective voice for trees, because it's clear he really truly cares.

Jad

You can hear it in his voice when he talks about trees.

Lilly

You can. This has been a really great conversation.

Jad

I agree. I feel like I learned so much preparing for this deep dive into Dirk Dujasuken's work. And you know, it's easy to take trees for granted, especially in a city. But he reminds us they're not just these passive things, they're alive and they're doing so much for us, even when we don't realize it.

Lilly

It's true, there are silent partners in this whole urban living experiment, aren't they?

Jad

They are and they deserve our protection. So next time you walk by a tree, maybe give it a little nod or something.

Lilly

I love that A little. Thank you for all the hard work.

Roger

Exactly A little. Thank you for all the hard work. Exactly Until next time everyone keep looking up. Thanks for tuning in to this special edition of Talking Trees. We hope you enjoyed this insightful conversation. We truly appreciate the support of our subscribers, as your contributions make it possible for us to bring you exclusive content like this. If you found this episode valuable, stay with us for more in-depth interviews and expert insights, available only to our subscribers. Until next time. Thank you for your continued support and keep growing your passion for trees. You.

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